Functional response of Telenomus remus (Hymenoptera: Scelionidae) to different egg densities of Spodoptera frugiperda (Lepidoptera: Noctuidae)
Pinto, Ciro Pedro GuidottiRomanello, Narian
ABSTRACT The parasitoid Telenomus remus Nixon (Hymenoptera: Scelionidae) is a natural enemy of lepidopteran pests, and several studies have been conducted to evaluate its efficiency on eggs of Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae). Functional response is an important parameter for assessing the potential of parasitoids. The objective of this work was to evaluate the harvesting behavior and the functional response of T. remus on eggs of S. frugiperda. We conducted the experiment in an acclimatized chamber at 25 ± 2°C, relative humidity 70% ± 10% and photophase of 12 hours. For harvesting behavior, we observed that a female takes 2.4 minutes, from the placement to the first cleaning, which is 44.7 seconds, to parasite one egg. The value of the quadratic coefficient was negative (P1 < 0.0005), so it can be assumed that the functional response of T. remus to eggs of S. frugiperda was type III. The results of attack rate (a'), handling time (Th ), and number of eggs parasitized at 24 hours by T. remus were, respectively, 0.00664 and 0.5649·h-1. The sex ratio of the parasitoid was influenced by host densities, with a ratio of 0.5 at 10 and 30 egg densities, but values were not differentiated from the density of 15 eggs. Our results can be helpful for developing field studies, enhancing the knowledge and possibilities for integrated pest management.
Texto completo